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src/Source/FreeImage/PluginJPEG.cpp  view on Meta::CPAN

	return TRUE indicating that the buffer has been dumped.
	free_in_buffer must be set to a positive value when TRUE is
	returned.  A FALSE return should only be used when I/O suspension is
	desired.
*/
METHODDEF(boolean)
empty_output_buffer (j_compress_ptr cinfo) {
	freeimage_dst_ptr dest = (freeimage_dst_ptr) cinfo->dest;

	if (dest->m_io->write_proc(dest->buffer, 1, OUTPUT_BUF_SIZE, dest->outfile) != OUTPUT_BUF_SIZE) {
		// let the memory manager delete any temp files before we die
		jpeg_destroy((j_common_ptr)cinfo);

		JPEG_EXIT((j_common_ptr)cinfo, JERR_FILE_WRITE);
	}

	dest->pub.next_output_byte = dest->buffer;
	dest->pub.free_in_buffer = OUTPUT_BUF_SIZE;

	return TRUE;
}

/**
	Terminate destination --- called by jpeg_finish_compress() after all
	data has been written.  In most applications, this must flush any
	data remaining in the buffer.  Use either next_output_byte or
	free_in_buffer to determine how much data is in the buffer.
*/
METHODDEF(void)
term_destination (j_compress_ptr cinfo) {
	freeimage_dst_ptr dest = (freeimage_dst_ptr) cinfo->dest;

	size_t datacount = OUTPUT_BUF_SIZE - dest->pub.free_in_buffer;

	// write any data remaining in the buffer

	if (datacount > 0) {
		if (dest->m_io->write_proc(dest->buffer, 1, (unsigned int)datacount, dest->outfile) != datacount) {
			// let the memory manager delete any temp files before we die
			jpeg_destroy((j_common_ptr)cinfo);
			
			JPEG_EXIT((j_common_ptr)cinfo, JERR_FILE_WRITE);
		}
	}
}

// ----------------------------------------------------------
//   Source manager
// ----------------------------------------------------------

/**
	Initialize source.  This is called by jpeg_read_header() before any
	data is actually read. Unlike init_destination(), it may leave
	bytes_in_buffer set to 0 (in which case a fill_input_buffer() call
	will occur immediately).
*/
METHODDEF(void)
init_source (j_decompress_ptr cinfo) {
	freeimage_src_ptr src = (freeimage_src_ptr) cinfo->src;

	/* We reset the empty-input-file flag for each image,
 	 * but we don't clear the input buffer.
	 * This is correct behavior for reading a series of images from one source.
	*/

	src->start_of_file = TRUE;
}

/**
	This is called whenever bytes_in_buffer has reached zero and more
	data is wanted.  In typical applications, it should read fresh data
	into the buffer (ignoring the current state of next_input_byte and
	bytes_in_buffer), reset the pointer & count to the start of the
	buffer, and return TRUE indicating that the buffer has been reloaded.
	It is not necessary to fill the buffer entirely, only to obtain at
	least one more byte.  bytes_in_buffer MUST be set to a positive value
	if TRUE is returned.  A FALSE return should only be used when I/O
	suspension is desired.
*/
METHODDEF(boolean)
fill_input_buffer (j_decompress_ptr cinfo) {
	freeimage_src_ptr src = (freeimage_src_ptr) cinfo->src;

	size_t nbytes = src->m_io->read_proc(src->buffer, 1, INPUT_BUF_SIZE, src->infile);

	if (nbytes <= 0) {
		if (src->start_of_file)	{
			// treat empty input file as fatal error

			// let the memory manager delete any temp files before we die
			jpeg_destroy((j_common_ptr)cinfo);

			JPEG_EXIT((j_common_ptr)cinfo, JERR_INPUT_EMPTY);
		}

		JPEG_WARNING((j_common_ptr)cinfo, JWRN_JPEG_EOF);

		/* Insert a fake EOI marker */

		src->buffer[0] = (JOCTET) 0xFF;
		src->buffer[1] = (JOCTET) JPEG_EOI;

		nbytes = 2;
	}

	src->pub.next_input_byte = src->buffer;
	src->pub.bytes_in_buffer = nbytes;
	src->start_of_file = FALSE;

	return TRUE;
}

/**
	Skip num_bytes worth of data.  The buffer pointer and count should
	be advanced over num_bytes input bytes, refilling the buffer as
	needed. This is used to skip over a potentially large amount of
	uninteresting data (such as an APPn marker). In some applications
	it may be possible to optimize away the reading of the skipped data,
	but it's not clear that being smart is worth much trouble; large
	skips are uncommon.  bytes_in_buffer may be zero on return.
	A zero or negative skip count should be treated as a no-op.

src/Source/FreeImage/PluginJPEG.cpp  view on Meta::CPAN

Format() {
	return "JPEG";
}

static const char * DLL_CALLCONV
Description() {
	return "JPEG - JFIF Compliant";
}

static const char * DLL_CALLCONV
Extension() {
	return "jpg,jif,jpeg,jpe";
}

static const char * DLL_CALLCONV
RegExpr() {
	return "^\377\330\377";
}

static const char * DLL_CALLCONV
MimeType() {
	return "image/jpeg";
}

static BOOL DLL_CALLCONV
Validate(FreeImageIO *io, fi_handle handle) {
	BYTE jpeg_signature[] = { 0xFF, 0xD8 };
	BYTE signature[2] = { 0, 0 };

	io->read_proc(signature, 1, sizeof(jpeg_signature), handle);

	return (memcmp(jpeg_signature, signature, sizeof(jpeg_signature)) == 0);
}

static BOOL DLL_CALLCONV
SupportsExportDepth(int depth) {
	return (
			(depth == 8) ||
			(depth == 24)
		);
}

static BOOL DLL_CALLCONV 
SupportsExportType(FREE_IMAGE_TYPE type) {
	return (type == FIT_BITMAP) ? TRUE : FALSE;
}

static BOOL DLL_CALLCONV
SupportsICCProfiles() {
	return TRUE;
}

static BOOL DLL_CALLCONV
SupportsNoPixels() {
	return TRUE;
}

// ----------------------------------------------------------

static FIBITMAP * DLL_CALLCONV
Load(FreeImageIO *io, fi_handle handle, int page, int flags, void *data) {
	if (handle) {
		FIBITMAP *dib = NULL;

		BOOL header_only = (flags & FIF_LOAD_NOPIXELS) == FIF_LOAD_NOPIXELS;

		// set up the jpeglib structures

		struct jpeg_decompress_struct cinfo;
		ErrorManager fi_error_mgr;

		try {

			// step 1: allocate and initialize JPEG decompression object

			// we set up the normal JPEG error routines, then override error_exit & output_message
			cinfo.err = jpeg_std_error(&fi_error_mgr.pub);
			fi_error_mgr.pub.error_exit     = jpeg_error_exit;
			fi_error_mgr.pub.output_message = jpeg_output_message;
			
			// establish the setjmp return context for jpeg_error_exit to use
			if (setjmp(fi_error_mgr.setjmp_buffer)) {
				// If we get here, the JPEG code has signaled an error.
				// We need to clean up the JPEG object, close the input file, and return.
				jpeg_destroy_decompress(&cinfo);
				throw (const char*)NULL;
			}

			jpeg_create_decompress(&cinfo);

			// step 2a: specify data source (eg, a handle)

			jpeg_freeimage_src(&cinfo, handle, io);

			// step 2b: save special markers for later reading
			
			jpeg_save_markers(&cinfo, JPEG_COM, 0xFFFF);
			for(int m = 0; m < 16; m++) {
				jpeg_save_markers(&cinfo, JPEG_APP0 + m, 0xFFFF);
			}

			// step 3: read handle parameters with jpeg_read_header()

			jpeg_read_header(&cinfo, TRUE);

			// step 4: set parameters for decompression

			unsigned int scale_denom = 1;		// fraction by which to scale image
			int	requested_size = flags >> 16;	// requested user size in pixels
			if(requested_size > 0) {
				// the JPEG codec can perform x2, x4 or x8 scaling on loading
				// try to find the more appropriate scaling according to user's need
				double scale = MAX((double)cinfo.image_width, (double)cinfo.image_height) / (double)requested_size;
				if(scale >= 8) {
					scale_denom = 8;
				} else if(scale >= 4) {
					scale_denom = 4;
				} else if(scale >= 2) {
					scale_denom = 2;
				}
			}
			cinfo.scale_num = 1;
			cinfo.scale_denom = scale_denom;

			if ((flags & JPEG_ACCURATE) != JPEG_ACCURATE) {
				cinfo.dct_method          = JDCT_IFAST;
				cinfo.do_fancy_upsampling = FALSE;
			}

			if ((flags & JPEG_GREYSCALE) == JPEG_GREYSCALE) {
				// force loading as a 8-bit greyscale image
				cinfo.out_color_space = JCS_GRAYSCALE;
			}

			// step 5a: start decompressor and calculate output width and height

			jpeg_start_decompress(&cinfo);

			// step 5b: allocate dib and init header

			if((cinfo.output_components == 4) && (cinfo.out_color_space == JCS_CMYK)) {
				// CMYK image
				if((flags & JPEG_CMYK) == JPEG_CMYK) {
					// load as CMYK
					dib = FreeImage_AllocateHeader(header_only, cinfo.output_width, cinfo.output_height, 32, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
					if(!dib) throw FI_MSG_ERROR_DIB_MEMORY;
					FreeImage_GetICCProfile(dib)->flags |= FIICC_COLOR_IS_CMYK;
				} else {
					// load as CMYK and convert to RGB
					dib = FreeImage_AllocateHeader(header_only, cinfo.output_width, cinfo.output_height, 24, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
					if(!dib) throw FI_MSG_ERROR_DIB_MEMORY;
				}
			} else {
				// RGB or greyscale image
				dib = FreeImage_AllocateHeader(header_only, cinfo.output_width, cinfo.output_height, 8 * cinfo.output_components, FI_RGBA_RED_MASK, FI_RGBA_GREEN_MASK, FI_RGBA_BLUE_MASK);
				if(!dib) throw FI_MSG_ERROR_DIB_MEMORY;

				if (cinfo.output_components == 1) {
					// build a greyscale palette
					RGBQUAD *colors = FreeImage_GetPalette(dib);

					for (int i = 0; i < 256; i++) {
						colors[i].rgbRed   = (BYTE)i;
						colors[i].rgbGreen = (BYTE)i;
						colors[i].rgbBlue  = (BYTE)i;
					}
				}
			}
			if(scale_denom != 1) {
				// store original size info if a scaling was requested
				store_size_info(dib, cinfo.image_width, cinfo.image_height);
			}

			// step 5c: handle metrices

			if (cinfo.density_unit == 1) {
				// dots/inch
				FreeImage_SetDotsPerMeterX(dib, (unsigned) (((float)cinfo.X_density) / 0.0254000 + 0.5));
				FreeImage_SetDotsPerMeterY(dib, (unsigned) (((float)cinfo.Y_density) / 0.0254000 + 0.5));
			} else if (cinfo.density_unit == 2) {
				// dots/cm
				FreeImage_SetDotsPerMeterX(dib, (unsigned) (cinfo.X_density * 100));
				FreeImage_SetDotsPerMeterY(dib, (unsigned) (cinfo.Y_density * 100));
			}
			
			// step 6: read special markers
			
			read_markers(&cinfo, dib);

			// --- header only mode => clean-up and return

			if (header_only) {
				// release JPEG decompression object
				jpeg_destroy_decompress(&cinfo);
				// return header data
				return dib;
			}

			// step 7a: while (scan lines remain to be read) jpeg_read_scanlines(...);

			if((cinfo.out_color_space == JCS_CMYK) && ((flags & JPEG_CMYK) != JPEG_CMYK)) {
				// convert from CMYK to RGB

				JSAMPARRAY buffer;		// output row buffer
				unsigned row_stride;	// physical row width in output buffer

				// JSAMPLEs per row in output buffer
				row_stride = cinfo.output_width * cinfo.output_components;
				// make a one-row-high sample array that will go away when done with image
				buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

				while (cinfo.output_scanline < cinfo.output_height) {
					JSAMPROW src = buffer[0];
					JSAMPROW dst = FreeImage_GetScanLine(dib, cinfo.output_height - cinfo.output_scanline - 1);

					jpeg_read_scanlines(&cinfo, buffer, 1);

					for(unsigned x = 0; x < cinfo.output_width; x++) {
						WORD K = (WORD)src[3];
						dst[FI_RGBA_RED]   = (BYTE)((K * src[0]) / 255);	// C -> R
						dst[FI_RGBA_GREEN] = (BYTE)((K * src[1]) / 255);	// M -> G
						dst[FI_RGBA_BLUE]  = (BYTE)((K * src[2]) / 255);	// Y -> B
						src += 4;
						dst += 3;
					}
				}
			} else if((cinfo.out_color_space == JCS_CMYK) && ((flags & JPEG_CMYK) == JPEG_CMYK)) {
				// convert from LibJPEG CMYK to standard CMYK

				JSAMPARRAY buffer;		// output row buffer
				unsigned row_stride;	// physical row width in output buffer

				// JSAMPLEs per row in output buffer
				row_stride = cinfo.output_width * cinfo.output_components;
				// make a one-row-high sample array that will go away when done with image
				buffer = (*cinfo.mem->alloc_sarray)((j_common_ptr) &cinfo, JPOOL_IMAGE, row_stride, 1);

				while (cinfo.output_scanline < cinfo.output_height) {
					JSAMPROW src = buffer[0];
					JSAMPROW dst = FreeImage_GetScanLine(dib, cinfo.output_height - cinfo.output_scanline - 1);

					jpeg_read_scanlines(&cinfo, buffer, 1);

					for(unsigned x = 0; x < cinfo.output_width; x++) {
						// CMYK pixels are inverted
						dst[0] = ~src[0];	// C
						dst[1] = ~src[1];	// M
						dst[2] = ~src[2];	// Y
						dst[3] = ~src[3];	// K
						src += 4;
						dst += 4;
					}
				}

			} else {
				// normal case (RGB or greyscale image)

				while (cinfo.output_scanline < cinfo.output_height) {
					JSAMPROW dst = FreeImage_GetScanLine(dib, cinfo.output_height - cinfo.output_scanline - 1);

					jpeg_read_scanlines(&cinfo, &dst, 1);
				}

				// step 7b: swap red and blue components (see LibJPEG/jmorecfg.h: #define RGB_RED, ...)
				// The default behavior of the JPEG library is kept "as is" because LibTIFF uses 
				// LibJPEG "as is".

#if FREEIMAGE_COLORORDER == FREEIMAGE_COLORORDER_BGR
				SwapRedBlue32(dib);
#endif
			}

			// step 8: finish decompression

			jpeg_finish_decompress(&cinfo);

			// step 9: release JPEG decompression object

			jpeg_destroy_decompress(&cinfo);

			// check for automatic Exif rotation
			if(!header_only && ((flags & JPEG_EXIFROTATE) == JPEG_EXIFROTATE)) {
				RotateExif(&dib);
			}

			// everything went well. return the loaded dib

			return dib;

		} catch (const char *text) {
			jpeg_destroy_decompress(&cinfo);
			if(NULL != dib) {
				FreeImage_Unload(dib);
			}
			if(NULL != text) {
				FreeImage_OutputMessageProc(s_format_id, text);
			}
		}
	}

	return NULL;
}

// ----------------------------------------------------------

static BOOL DLL_CALLCONV
Save(FreeImageIO *io, FIBITMAP *dib, fi_handle handle, int page, int flags, void *data) {
	if ((dib) && (handle)) {
		try {
			// Check dib format

			const char *sError = "only 24-bit highcolor or 8-bit greyscale/palette bitmaps can be saved as JPEG";

			FREE_IMAGE_COLOR_TYPE color_type = FreeImage_GetColorType(dib);
			WORD bpp = (WORD)FreeImage_GetBPP(dib);

			if ((bpp != 24) && (bpp != 8)) {
				throw sError;
			}

			if(bpp == 8) {
				// allow grey, reverse grey and palette 
				if ((color_type != FIC_MINISBLACK) && (color_type != FIC_MINISWHITE) && (color_type != FIC_PALETTE)) {
					throw sError;
				}
			}


			struct jpeg_compress_struct cinfo;
			ErrorManager fi_error_mgr;

			// Step 1: allocate and initialize JPEG compression object

			// we set up the normal JPEG error routines, then override error_exit & output_message
			cinfo.err = jpeg_std_error(&fi_error_mgr.pub);
			fi_error_mgr.pub.error_exit     = jpeg_error_exit;
			fi_error_mgr.pub.output_message = jpeg_output_message;
			
			// establish the setjmp return context for jpeg_error_exit to use
			if (setjmp(fi_error_mgr.setjmp_buffer)) {
				// If we get here, the JPEG code has signaled an error.
				// We need to clean up the JPEG object, close the input file, and return.
				jpeg_destroy_compress(&cinfo);
				throw (const char*)NULL;
			}

			// Now we can initialize the JPEG compression object

			jpeg_create_compress(&cinfo);

			// Step 2: specify data destination (eg, a file)

			jpeg_freeimage_dst(&cinfo, handle, io);

			// Step 3: set parameters for compression 

			cinfo.image_width = FreeImage_GetWidth(dib);
			cinfo.image_height = FreeImage_GetHeight(dib);

			switch(color_type) {
				case FIC_MINISBLACK :
				case FIC_MINISWHITE :
					cinfo.in_color_space = JCS_GRAYSCALE;
					cinfo.input_components = 1;
					break;

				default :
					cinfo.in_color_space = JCS_RGB;
					cinfo.input_components = 3;
					break;
			}

			jpeg_set_defaults(&cinfo);

		    // progressive-JPEG support
			if((flags & JPEG_PROGRESSIVE) == JPEG_PROGRESSIVE) {
				jpeg_simple_progression(&cinfo);
			}
			
			// compute optimal Huffman coding tables for the image
			if((flags & JPEG_OPTIMIZE) == JPEG_OPTIMIZE) {
				cinfo.optimize_coding = TRUE;
			}

			// Set JFIF density parameters from the DIB data

			cinfo.X_density = (UINT16) (0.5 + 0.0254 * FreeImage_GetDotsPerMeterX(dib));
			cinfo.Y_density = (UINT16) (0.5 + 0.0254 * FreeImage_GetDotsPerMeterY(dib));
			cinfo.density_unit = 1;	// dots / inch

			// thumbnail support (JFIF 1.02 extension markers)
			if(FreeImage_GetThumbnail(dib) != NULL) {
				cinfo.write_JFIF_header = 1; //<### force it, though when color is CMYK it will be incorrect
				cinfo.JFIF_minor_version = 2;
			}

			// baseline JPEG support
			if ((flags & JPEG_BASELINE) ==  JPEG_BASELINE) {
				cinfo.write_JFIF_header = 0;	// No marker for non-JFIF colorspaces
				cinfo.write_Adobe_marker = 0;	// write no Adobe marker by default				
			}

			// set subsampling options if required

			if(cinfo.in_color_space == JCS_RGB) {
				if((flags & JPEG_SUBSAMPLING_411) == JPEG_SUBSAMPLING_411) { 
					// 4:1:1 (4x1 1x1 1x1) - CrH 25% - CbH 25% - CrV 100% - CbV 100%
					// the horizontal color resolution is quartered
					cinfo.comp_info[0].h_samp_factor = 4;	// Y 
					cinfo.comp_info[0].v_samp_factor = 1; 
					cinfo.comp_info[1].h_samp_factor = 1;	// Cb 
					cinfo.comp_info[1].v_samp_factor = 1; 
					cinfo.comp_info[2].h_samp_factor = 1;	// Cr 
					cinfo.comp_info[2].v_samp_factor = 1; 
				} else if((flags & JPEG_SUBSAMPLING_420) == JPEG_SUBSAMPLING_420) {
					// 4:2:0 (2x2 1x1 1x1) - CrH 50% - CbH 50% - CrV 50% - CbV 50%
					// the chrominance resolution in both the horizontal and vertical directions is cut in half
					cinfo.comp_info[0].h_samp_factor = 2;	// Y
					cinfo.comp_info[0].v_samp_factor = 2; 
					cinfo.comp_info[1].h_samp_factor = 1;	// Cb
					cinfo.comp_info[1].v_samp_factor = 1; 
					cinfo.comp_info[2].h_samp_factor = 1;	// Cr
					cinfo.comp_info[2].v_samp_factor = 1; 
				} else if((flags & JPEG_SUBSAMPLING_422) == JPEG_SUBSAMPLING_422){ //2x1 (low) 
					// 4:2:2 (2x1 1x1 1x1) - CrH 50% - CbH 50% - CrV 100% - CbV 100%
					// half of the horizontal resolution in the chrominance is dropped (Cb & Cr), 
					// while the full resolution is retained in the vertical direction, with respect to the luminance
					cinfo.comp_info[0].h_samp_factor = 2;	// Y 
					cinfo.comp_info[0].v_samp_factor = 1; 
					cinfo.comp_info[1].h_samp_factor = 1;	// Cb 
					cinfo.comp_info[1].v_samp_factor = 1; 
					cinfo.comp_info[2].h_samp_factor = 1;	// Cr 
					cinfo.comp_info[2].v_samp_factor = 1; 
				} 
				else if((flags & JPEG_SUBSAMPLING_444) == JPEG_SUBSAMPLING_444){ //1x1 (no subsampling) 
					// 4:4:4 (1x1 1x1 1x1) - CrH 100% - CbH 100% - CrV 100% - CbV 100%
					// the resolution of chrominance information (Cb & Cr) is preserved 
					// at the same rate as the luminance (Y) information
					cinfo.comp_info[0].h_samp_factor = 1;	// Y 
					cinfo.comp_info[0].v_samp_factor = 1; 
					cinfo.comp_info[1].h_samp_factor = 1;	// Cb 
					cinfo.comp_info[1].v_samp_factor = 1; 
					cinfo.comp_info[2].h_samp_factor = 1;	// Cr 
					cinfo.comp_info[2].v_samp_factor = 1;  
				} 
			}

			// Step 4: set quality
			// the first 7 bits are reserved for low level quality settings
			// the other bits are high level (i.e. enum-ish)

			int quality;

			if ((flags & JPEG_QUALITYBAD) == JPEG_QUALITYBAD) {
				quality = 10;
			} else if ((flags & JPEG_QUALITYAVERAGE) == JPEG_QUALITYAVERAGE) {
				quality = 25;
			} else if ((flags & JPEG_QUALITYNORMAL) == JPEG_QUALITYNORMAL) {
				quality = 50;
			} else if ((flags & JPEG_QUALITYGOOD) == JPEG_QUALITYGOOD) {
				quality = 75;
			} else 	if ((flags & JPEG_QUALITYSUPERB) == JPEG_QUALITYSUPERB) {
				quality = 100;
			} else {
				if ((flags & 0x7F) == 0) {
					quality = 75;
				} else {
					quality = flags & 0x7F;
				}
			}

			jpeg_set_quality(&cinfo, quality, TRUE); /* limit to baseline-JPEG values */

			// Step 5: Start compressor 

			jpeg_start_compress(&cinfo, TRUE);

			// Step 6: Write special markers
			
			if ((flags & JPEG_BASELINE) !=  JPEG_BASELINE) {
				write_markers(&cinfo, dib);
			}

			// Step 7: while (scan lines remain to be written) 

			if(color_type == FIC_RGB) {
				// 24-bit RGB image : need to swap red and blue channels
				unsigned pitch = FreeImage_GetPitch(dib);
				BYTE *target = (BYTE*)malloc(pitch * sizeof(BYTE));
				if (target == NULL) {
					throw FI_MSG_ERROR_MEMORY;
				}

				while (cinfo.next_scanline < cinfo.image_height) {
					// get a copy of the scanline
					memcpy(target, FreeImage_GetScanLine(dib, FreeImage_GetHeight(dib) - cinfo.next_scanline - 1), pitch);
#if FREEIMAGE_COLORORDER == FREEIMAGE_COLORORDER_BGR
					// swap R and B channels
					BYTE *target_p = target;
					for(unsigned x = 0; x < cinfo.image_width; x++) {
						INPLACESWAP(target_p[0], target_p[2]);
						target_p += 3;
					}
#endif
					// write the scanline
					jpeg_write_scanlines(&cinfo, &target, 1);
				}
				free(target);
			}
			else if(color_type == FIC_MINISBLACK) {
				// 8-bit standard greyscale images
				while (cinfo.next_scanline < cinfo.image_height) {
					JSAMPROW b = FreeImage_GetScanLine(dib, FreeImage_GetHeight(dib) - cinfo.next_scanline - 1);

					jpeg_write_scanlines(&cinfo, &b, 1);
				}
			}
			else if(color_type == FIC_PALETTE) {
				// 8-bit palettized images are converted to 24-bit images
				RGBQUAD *palette = FreeImage_GetPalette(dib);
				BYTE *target = (BYTE*)malloc(cinfo.image_width * 3);
				if (target == NULL) {
					throw FI_MSG_ERROR_MEMORY;
				}

				while (cinfo.next_scanline < cinfo.image_height) {
					BYTE *source = FreeImage_GetScanLine(dib, FreeImage_GetHeight(dib) - cinfo.next_scanline - 1);
					FreeImage_ConvertLine8To24(target, source, cinfo.image_width, palette);

#if FREEIMAGE_COLORORDER == FREEIMAGE_COLORORDER_BGR
					// swap R and B channels
					BYTE *target_p = target;
					for(unsigned x = 0; x < cinfo.image_width; x++) {
						INPLACESWAP(target_p[0], target_p[2]);
						target_p += 3;
					}
#endif


					jpeg_write_scanlines(&cinfo, &target, 1);